From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EF16AC433DF for ; Thu, 13 Aug 2020 12:58:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D36A520791 for ; Thu, 13 Aug 2020 12:58:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726639AbgHMM6j (ORCPT ); Thu, 13 Aug 2020 08:58:39 -0400 Received: from mx2.suse.de ([195.135.220.15]:41954 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726102AbgHMM6i (ORCPT ); Thu, 13 Aug 2020 08:58:38 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 28504AC55; Thu, 13 Aug 2020 12:58:59 +0000 (UTC) Date: Thu, 13 Aug 2020 14:58:36 +0200 Message-ID: From: Takashi Iwai To: Prateek Sood Cc: mcgrof@kernel.org, gregkh@linuxfoundation.org, rafael@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] firmware_loader: fix memory leak for paged buffer In-Reply-To: <1597258819-14080-1-git-send-email-prsood@codeaurora.org> References: <1597258819-14080-1-git-send-email-prsood@codeaurora.org> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.3 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 12 Aug 2020 21:00:19 +0200, Prateek Sood wrote: > > vfree() is being called on paged buffer allocated > using alloc_page() and mapped using vmap(). > > Freeing of pages in vfree() relies on nr_pages of > struct vm_struct. vmap() does not update nr_pages. > It can lead to memory leaks. > > Signed-off-by: Prateek Sood Thanks for spotting this out! This is essentially a revert of the commit ddaf29fd9bb6 ("firmware: Free temporary page table after vmapping"), so better to mention it via Fixes tag as well as Cc to stable. About the changes: > --- a/drivers/base/firmware_loader/firmware.h > +++ b/drivers/base/firmware_loader/firmware.h > @@ -142,10 +142,12 @@ static inline void fw_state_done(struct fw_priv *fw_priv) > void fw_free_paged_buf(struct fw_priv *fw_priv); > int fw_grow_paged_buf(struct fw_priv *fw_priv, int pages_needed); > int fw_map_paged_buf(struct fw_priv *fw_priv); > +bool fw_is_paged_buf(struct fw_priv *fw_priv); I guess this isn't necessary if we just swap the call order of fw_free_paged_buf() and vfree(); then fw_priv->is_paged_buf is referred only in fw_free_paged_buf(). That is, something like below. In anyway, take my review tag: Reviewed-by: Takashi Iwai thanks, Takashi --- a/drivers/base/firmware_loader/main.c +++ b/drivers/base/firmware_loader/main.c @@ -252,9 +252,9 @@ static void __free_fw_priv(struct kref *ref) list_del(&fw_priv->list); spin_unlock(&fwc->lock); - fw_free_paged_buf(fw_priv); /* free leftover pages */ if (!fw_priv->allocated_size) vfree(fw_priv->data); + fw_free_paged_buf(fw_priv); /* free leftover pages */ kfree_const(fw_priv->fw_name); kfree(fw_priv); } @@ -272,7 +272,7 @@ void fw_free_paged_buf(struct fw_priv *fw_priv) { int i; - if (!fw_priv->pages) + if (!fw_priv->is_paged_buf) return; for (i = 0; i < fw_priv->nr_pages; i++) @@ -328,10 +328,6 @@ int fw_map_paged_buf(struct fw_priv *fw_priv) if (!fw_priv->data) return -ENOMEM; - /* page table is no longer needed after mapping, let's free */ - kvfree(fw_priv->pages); - fw_priv->pages = NULL; - return 0; } #endif